JP2000104769A - Disc brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disc brake suitable for improvement of operating precision and improvement of maintainability by eliminating hydraulic piping between a cylinder on a caliper body and an electric hydraulic oil pressure generator. SOLUTION: An electric hydraulic oil pressure generator 15 to supply oil pressure to a cylinder 13 is built in a caliper body with a solid element free to electrically control expanding and contracting motion as a driving source and is connected to a cylinder 13 through an oil passage 29 formed on the caliper body itself in a disc brake 1 on which a piston 9 in the cylinder 13 presses a friction pad on the rotor 3 by oil pressure to be supplied to the caliper body 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc brake having a piston slidable in a cylinder of a caliper body, wherein the piston presses a friction pad against a rotor by hydraulic pressure supplied to the cylinder. Is
The present invention relates to an improvement for improving operation accuracy and maintainability.

[0002]

2. Description of the Related Art In recent years, brake systems for vehicles have been actively provided with intelligent brake functions such as an anti-lock brake system and a traction control system. With such intelligence, it has become indispensable to make the hydraulic pressure generating device (pump) incorporated as a hydraulic pressure generating source into a brake device electrically driven and downsized.

[0003] From such a background, a pump unit that discharges a fluid by reciprocating a piston housed in a housing, and a piston that uses a solid element that can electrically control expansion and contraction as a driving source for reciprocating the piston. There has been proposed an electric hydraulic pressure generating device including a driving unit. In this case,
Piezoelectric ceramics and giant magnetostrictive elements have been proposed as solid-state elements whose expansion and contraction operations can be electrically controlled (Japanese Unexamined Patent Publication No.
167327, JP-A-8-334082, etc.).

[0004] Conventionally, as a hydraulic disc brake, which is electrified by use of such an electric hydraulic pressure generating device, an electric hydraulic pressure generating device is installed near a brake operating section and mounted near wheels. There have been proposed various types of structures in which a cylinder of a brake unit and an electric hydraulic pressure generator are connected by a hydraulic pipe.

[0005]

However, in the above-described structure, the transmission of the hydraulic pressure from the electric hydraulic pressure generator to the cylinder is delayed because the length of the hydraulic pipe between the cylinder and the electric hydraulic pressure generator is long. However, there is a problem that it is difficult to improve operation accuracy in terms of responsiveness. Also, in order to prevent the hydraulic piping from being damaged by stepping stones, etc., it is necessary to devise a routing route for the hydraulic piping, or to install a protective cover, etc., which reduces the degree of freedom in layout design and increases costs. There was a problem of inviting. Furthermore, it has been pointed out that long hydraulic piping inspection is indispensable for maintaining the safety of the brake, and that the inspection location is wide and the maintenance performance is poor.

The present invention has been made in view of the above circumstances, and eliminates the need for a hydraulic pipe connecting a cylinder of a brake unit and an electric hydraulic pressure generator, thereby enabling transmission of hydraulic pressure from the electric hydraulic pressure generator to the cylinder. Since there is no hydraulic piping, measures to protect hydraulic piping can be omitted, and disc brakes that can improve maintenance by reducing the number of inspection points to maintain brake safety. The purpose is to provide.

[0007]

A disk brake according to the present invention for achieving the above object has a piston slidable in a cylinder of a caliper body, and the piston is frictionally moved by hydraulic pressure supplied to the cylinder. In a disk brake that presses a pad against a rotor, an electric hydraulic pressure generator that supplies oil pressure to the cylinder generates hydraulic pressure in response to a brake operation using a solid element that can electrically control expansion and contraction operations as a drive source, The electric hydraulic pressure generator is housed in the caliper body.

According to the above configuration, since the electric hydraulic pressure generating device is incorporated into the caliper body itself of the brake unit, the hydraulic path for guiding the hydraulic pressure to the cylinder is provided in the caliper body itself. Hydraulic piping connecting the cylinder and the electric hydraulic pressure generator in the structure can be omitted, and the distance between the cylinder and the electric hydraulic pressure generator can be extremely short, so that the hydraulic pressure transmission time can be reduced. . In addition, since the control device for operating the electric hydraulic pressure generating device in response to the brake operation and the electric hydraulic pressure generating device are only connected by the electric wiring path, the hydraulic pressure generating device is compared with the hydraulic piping of the conventional structure. Therefore, defects in the middle of the line due to continuity check or the like can be easily inspected. Further, the inspection of the electric hydraulic pressure generator can be performed at the time of inspection of the cylinder of the caliper body, and the number of inspection points for maintaining the safety of the brake can be reduced.

Preferably, the caliper body has a bridge section that straddles the outer periphery of the rotor, and the electric hydraulic pressure generating device is housed in the bridge section. In this case, since the bridge portion has a pipe structure due to the provision of the hollow portion that accommodates the electric hydraulic pressure generating device, the weight of the bridge portion and the caliper body as a whole is reduced as compared with a solid structure. Can be strengthened.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a disc brake according to the present invention will be described below in detail with reference to the drawings.
1 to 3 show an embodiment of a disc brake according to the present invention. FIG. 1 is a front view of a main part of the disc brake according to the present invention, FIG. 2 is a partially cutaway side view of FIG. 3
FIG. 2 is a longitudinal sectional view of an electric hydraulic pressure generator incorporated in the caliper body of FIG. 1.

The disk brake 1 is a floating caliper type disk brake called a pin slide type, and has a disk-shaped rotor 3 which rotates integrally with wheels.
, A pair of friction pads 5, 6 opposed to each other across the rotor 3, a caliper body 7 having a piston 9 for pressing the friction pads 5, 6 against the rotor 3, and a caliper body 7 fixed to the vehicle body side Support 11 for supporting
And a caliper body 7 for slidably housing the piston 9
The upper cylinder 13 is provided with an electric hydraulic pressure generator 15 for supplying a hydraulic pressure according to the brake operation.

The caliper body 7 is provided at one end side of a bridge portion 17 straddling the outer periphery of the rotor 3 with a cylinder 13 in which a piston 9 for pressing one friction pad 5 against the rotor 3 is slidably accommodated in the axial direction of the rotor. At the same time, a reaction portion 19 for pressing the back surface of the other friction pad 6 is formed on the other end of the bridge portion 17. The bridge portion 17 is provided with a hydraulic pressure source housing portion 21 for housing the electric hydraulic pressure generating device 15. Cylinder 13
Is provided with a seal member 23 for hermetically sealing between the piston 9 and the sliding piston 9.

The support pin 11 is fixed to the vehicle body and is slidably fitted in a pair of caliper support holes penetrating along the axial direction of the rotor 3.
The caliper body 7 is floatingly supported by 5 and 25 so as to be movable in the axial direction of the rotor 3.

The electric hydraulic pressure generator 15 is a pump that generates hydraulic pressure by using a solid element capable of electrically controlling the expansion and contraction operation as a drive source. As shown in FIG.
The piston 153 accommodated in the first magnetostrictive element 1 is a solid-state element that is in contact with the piston 153 and is electrically controllable.
The pump unit 157 is configured to include a pump unit 157 that discharges a fluid by reciprocating by the expansion and contraction operation of 55.

In the pump section 157, a liquid chamber 159 is defined between the piston 153 and the end of the housing 151, and a discharge port 159a communicating with the liquid chamber 159 and discharging hydraulic oil by a pump action. A suction port 159b for sucking hydraulic oil, a reservoir 161 for storing hydraulic oil supplied to the liquid chamber 159, a reservoir 161 and the suction port 159.
b, the first oil passage 163 and the first oil passage 163 and the discharge port 159 a are connected to the liquid chamber 27 of the cylinder 13.
A second oil passage 165 communicating with (see FIG. 2) is formed. As shown in FIG. 2, the second oil passage 165 of the electric hydraulic pressure generating device 15 housed in the hydraulic power source housing 21 of the bridge portion 17 communicates with the caliper body 7 to the liquid chamber 27 of the cylinder 13. (See FIG. 1).

The discharge port 159a and the suction port 159b are provided with check valves 167 and 169, respectively, and the second oil passage 165 is normally controlled in operation by a control signal from a control circuit 31 described later. A closed solenoid valve 171 is provided. Check valve 167 at discharge port 159a
Opens the flow path during the discharge stroke of the piston 153 and closes the flow path during the suction stroke. On the other hand, the check valve 169 of the suction port 159b opens the flow path during the suction stroke, and closes the flow path during the discharge stroke. The solenoid valve 171 operates when the pump operates (that is,
During the braking operation), the flow path is kept closed to prevent the discharge port 159a from communicating with the reservoir 161 and the suction port 159b, and when the pump is not operating (that is, during non-braking), The flow path is opened, and the operating oil sent from the cylinder 13 is returned to the reservoir 161 via the second oil passage 165.

The housing 15 in which the piston 153 slides
A piston seal 173 for airtightness between the piston 153 and the piston 153 is provided on an inner peripheral surface of the piston 1. Piston 153
Is urged by a return spring 175 arranged in the liquid chamber 159 in a direction away from the end of the liquid chamber (that is, in a direction contacting the giant magnetostrictive element 155 as a solid element).

The electric hydraulic pressure generating device 15 includes the above-described giant magnetostrictive element 155 having a characteristic of extending when a magnetic field is further applied, a coil 177 for applying a magnetic field to the giant magnetostrictive element 155 when a current is applied, The giant magnetostrictive element 155 is moved so that the expansion / contraction operation of the giant magnetostrictive element 155 is transmitted to the piston 153.
And a coil 151 that accommodates and holds the coil 177 inside the cylinder, and an electromagnetic valve 171 that opens the second oil passage 165 to release the brake pressure to the reservoir 161 when braking is not performed.

Control of the current applied to the giant magnetostrictive element 155,
The operation control of the solenoid valve 171 is performed by a control circuit 31 provided on the vehicle body separately from the electric hydraulic pressure generator 15.

The housing 151 slidably accommodates and holds the piston 153 inside the cylinder continuously to the accommodating area of the giant magnetostrictive element 155 and the coil 177 so that the expansion and contraction operation of the giant magnetostrictive element 155 is transmitted to the piston 153. At the same time, it functions as a yoke constituting a closed magnetic circuit that covers these areas. Further, the return spring 175 of the piston 153 also functions as a preload spring that makes the extension operation of the giant magnetostrictive element 155 more efficient.

The control circuit 31 includes a pump operation control circuit (not shown) that causes the giant magnetostrictive element 155 to expand and contract at a predetermined cycle by applying a current to the coil 177 in order to cause the piston 153 to reciprocate properly during a braking operation or the like. An electromagnetic valve control circuit (not shown) for controlling the operation of the electromagnetic valve 171 is provided.

The amount of expansion and contraction of the giant magnetostrictive element 155
7 is proportional to the strength of the applied magnetic field. Therefore, during the discharge stroke by the piston 153, the magnetic field generated by the coil 177 is increased from the initial value to a predetermined value.
The suction stroke is performed by lowering the magnetic field generated by the coil 177 from a predetermined value to an initial value, and causing the giant magnetostrictive element 155 to perform a predetermined contraction operation.

The pump operation control circuit of the control circuit 31 controls the current applied to the coil 177 so that the magnetic field generated by the coil 177 rises from an initial value to a predetermined value during the discharge stroke by the piston 153. Further, during the suction stroke, the current applied to the coil 177 is controlled so that the magnetic field generated by the coil 177 drops from a predetermined value to an initial value. The pump operation control circuit realizes such repetition of the discharge step and the suction step by setting the current supplied to the coil 177 to an alternating current having a predetermined cycle.

The above-described electric hydraulic pressure generating device 15 includes a hydraulic power source housing 2 formed in the bridge portion 17 of the caliper body 7.
1 is stored in a state of being almost tightly fitted thereto, and is operation-controlled by a control circuit 31 installed around a brake operation unit such as a brake pedal, for example.

Next, the disk brake 1 having the above-described structure will be described.
The operation method will be described. At the time of a braking operation, for example, when a brake pedal (not shown) is depressed, the control circuit 31 controls the drive of the electric hydraulic pressure generator 15 based on an electric signal corresponding to the brake depression force, and causes the giant magnetostrictive element 155 to expand and contract. Due to the expansion and contraction operation, the pump 157 moves the reservoir 161 from the first oil passage 163 and the check valve 169.
The working oil is sucked into the liquid chamber 159 via the suction port 159b, and is discharged via the discharge port 159a and the check valve 167. The hydraulic pressure generated by this discharge is supplied to the liquid chamber 27 of the cylinder 13 via the second oil passage 165 and the oil passage 29 of the caliper body 7. As a result, the piston 9 slides in the cylinder 13 in the axial direction of the rotor to press one friction pad 5 against the rotor 3. When one friction pad 5 is pressed against the rotor 3, the reaction causes the floatingly supported caliper body 7 to move to the left as shown in FIG. 2 and the reaction portion 19 presses the other friction pad 6 against the rotor 3. Then, a braking force is generated. At the time of the above-described braking operation, the control circuit 31 controls the solenoid valve 171 to be in the closed state, and the discharge port 159a is connected to the reservoir 161.
And communication with the suction port 159b.

When the braking operation is released, the control circuit 31 stops the operation of the pump section 157 and opens the solenoid valve 171 to supply the operating oil sent to the cylinder 13 to the oil passage 29 of the caliper body 7 through the second oil passage 29. Return to the reservoir 161 via the oil passage 165. As a result, the piston 9 in the cylinder 13 is pushed back in a direction away from the rotor 3, and the braking force is released. At the time when the hydraulic oil is sufficiently absorbed into the reservoir 161, the solenoid valve 171 is closed to be in a steady state (non-braking state).

In the above-described disc brake 1, the electric hydraulic pressure generating device 15 is connected to the caliper body 7 of the brake unit.
The cylinder 13 on the caliper body 7 and the electric hydraulic pressure generating device are provided with a hydraulic path 29 that is incorporated in the motor itself and guides the hydraulic pressure generated by the electric hydraulic pressure generating device 15 in the caliper body 7 itself. 15 can be omitted. Also, the cylinder 13 on the caliper body 7
Since the distance between the motor and the electric hydraulic pressure generating device 15 can be extremely reduced, the pressure loss can be minimized and the hydraulic pressure transmission time can be shortened. Accordingly, the hydraulic pressure can be efficiently transmitted from the electric hydraulic pressure generating device 15 to the cylinder 13, and the operational accuracy can be easily improved in terms of responsiveness. In addition, since the hydraulic piping is omitted and measures for protecting the piping are not required, the degree of freedom in arrangement design and the cost can be reduced.

Also, when compared with a conventional disc brake provided with an electric hydraulic pressure generating device near the brake operating section, a control device and an electric hydraulic pressure generating device for operating the electric hydraulic pressure generating device according to the brake operation are provided. 15 is longer, but the electric wiring path can be easily inspected for defects in the middle of the line due to continuity check and the like, and can be easily protected against stepping stones and the like, as compared with hydraulic piping. .

Further, the electric hydraulic pressure generator 15 can be inspected when the cylinder 13 of the caliper body 7 is inspected or the like. It can also be improved.

In the present embodiment, the caliper body 7
Is a configuration in which the electric hydraulic pressure generating device 15 is accommodated in a bridge portion 17 that straddles the outer periphery of the rotor 3. Therefore, the rigidity of the bridge portion 17 and the caliper body 7 as a whole can be enhanced while suppressing weight increase as compared with the case of the solid structure, and the braking performance can be improved by improving the rigidity.

The location of the electric hydraulic pressure generating device 15 is not limited to the bridge portion 17 of the caliper body 7. The point is that the hydraulic piping from the electric hydraulic pressure generating device 15 to the cylinder 13 may be eliminated, and the mounting position of the electric hydraulic pressure generating device 15 is, for example, provided at the other end of the bridge portion 17 on the caliper body 7. Reaction part 19
May be set, and if space permits, the bridge portion 17 may be provided adjacent to the cylinder 13 at one end.

The electric hydraulic pressure generating device 15 of the above-described embodiment uses the giant magnetostrictive element 155 as a solid element capable of electrically controlling the expansion and contraction operation. Alternatively, a piezoelectric ceramic or the like can be used as the element.

The present invention is not limited to a disk brake in which the support floats and supports the caliper body so as to be movable in the axial direction of the rotor. For example, the support fixedly supports the caliper body, and the caliper body covers the outer periphery of the rotor. It can be applied to a so-called opposed disc brake or the like having cylinders for accommodating pistons on both sides of a bridging bridge.

The mounting position of the control circuit 31 for controlling the operation of the electric hydraulic pressure generating device 15 is not limited to the vicinity of the brake operating section. It may be set appropriately in consideration of the wiring layout and the like, and the relationship with other in-vehicle control devices.

[0035]

According to the disc brake of the present invention, the electric hydraulic pressure generator is incorporated in the caliper body itself of the brake unit, and the hydraulic pressure generated by the electric hydraulic pressure generator is guided to the cylinder on the caliper body. The road
Since the caliper body is drilled and installed, the need for hydraulic piping between the caliper body and the electric hydraulic generator can be eliminated, and the distance between the caliper body and the electric hydraulic generator can be reduced. Can be brought very close to each other, so that the transmission time of the hydraulic pressure can be shortened. Therefore, the hydraulic pressure can be efficiently transmitted from the electric hydraulic pressure generating device to the cylinder, and the operational accuracy can be easily improved in terms of responsiveness. In addition, since the measures for protecting the piping are not required, the degree of freedom in the layout design and the cost can be reduced.

Also, when compared with a conventional disc brake equipped with an electric hydraulic pressure generating device near the brake operating section, a difference between the control device that operates the electric hydraulic pressure generating device in response to the brake operation and the electric hydraulic pressure generating device. Although the electric wiring path becomes longer, the electric wiring path can be easily inspected for defects in the middle of the line due to continuity check and the like, and can be more easily protected against stepping stones and the like than hydraulic lines. Further, the electric hydraulic pressure generator can be inspected at the time of inspecting the cylinder of the caliper body and the like, and maintenance can be improved by reducing the number of inspection points for maintaining brake safety. .

According to the second aspect of the present invention, since the bridge portion of the caliper body has a pipe structure due to the provision of the hollow portion for accommodating the electric hydraulic pressure generating device, the bridge portion is compared with the solid structure. In addition, the rigidity of the bridge portion and the entire caliper body can be enhanced while suppressing weight increase, and braking performance can be improved by improving the rigidity.

[Brief description of the drawings]

FIG. 1 is a front view of a main part of a disc brake according to the present invention.

FIG. 2 is a partially cutaway side view of the disc brake according to the present invention.

FIG. 3 is a longitudinal sectional view showing a configuration of an electric hydraulic pressure generator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Disc brake 3 Rotor 7 Caliper body 9 Piston 11 Support 13 Cylinder 15 Electric hydraulic pressure generator 17 Bridge part 21 Hydraulic power source accommodation part 29 Oil passage

Claims (2)

[Claims] 1. A disc brake having a piston slidable in a cylinder of a caliper body, wherein the piston presses a friction pad against a rotor by hydraulic pressure supplied to the cylinder, wherein hydraulic pressure is supplied to the cylinder. The electric hydraulic pressure generating device is configured to generate a hydraulic pressure according to a brake operation by using a solid element capable of electrically controlling the expansion and contraction operation as a drive source, and the electric hydraulic pressure generating device is housed in the caliper body. Disc brake characterized by the following. 2. The disc brake according to claim 1, wherein the caliper body has a bridge section that straddles the outer periphery of the rotor, and the electric hydraulic pressure generating device is housed in the bridge section. brake.